Reproduction transfer sheet and method of making

ABSTRACT

THE PRESENT INVENTION RELATES TO REPRODUCTION TRANSFER SHEETS PREPARED BY COATING THE UPPER SIDES OF WHITE OR LIGHTLY COLORED SHEETS WITH A SOLUTION OF POLYETHYLENE IN TETACHLORETHYLENE CONTAINING DARK COLORED PIGMENTS OR DYES, AT A TEMPERATURE NOT SUBSTANTIALLY LOWER THAN 80* C. AFTER REMOVAL OF THE TETRACHLOROETHYLENE SOLVENT A WHITE OR LIGHTLY COLORED COATING OF POLYEHTYLENE MIXED WITH, FOR EXAMPLE, TITANIUM DIOXIDE, IS APPLIED OVER THE INITIAL COLORED COATING IN THE FORM OF A TETRACHLOROETHYLENE SOLUTION, AT A TEMPERATURE BELOW 80*C. AFTER REMOVAL OF THE SOLVENT. A WHITE OR LIGHTLY COLORED COATING IS APPLIED TO THE REVERSE SIDE OF THE SHEET. THIS COATING CONSISTS OF MICROCRYSTALLINE WAX TO WHICH TITANIUM DIOXIDE OR OTHER LIGHT COLORED PIGMENT MAY BE ADDED AS A BRIGHTENER. IF DESIRED, OTHER MATERIALS MAY ALSO BE INCLUDED IN THE COATING, AS FOR EXAMPLE, MAGNESIUM STEARATE FOR THE PURPOSE OF INCREASING THE ADHERENCE OF THE COATING.   D R A W I N G

United States Patent 3,561,992 REPRODUCTION TRANSFER SHEET AND METHOD OF MAKING Edgar Breidthardt, Dusseldorf, Germany, assignor to Ancar A.G., Zug, Switzerland Continuation-impart of applications Ser. N 0. 243,466,

Dec. 16, 1962, and Ser. No. 498,978, Oct. 20, 1965.

This application Nov. 9, 1967, Ser. No. 681,696 Claims priority, application 6G9er'many, Dec. 14, 1961,

U.S. Cl. 117-363 9 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to reproduction transfer sheets prepared by coating the upper sides of white or lightly colored sheets with a solution of polyethylene in tetrachloroethylene containing dark colored pigments or dyes, at a temperature not substantially lower than 80 C. After removal of the tetrachloroethylene solvent a white or lightly colored coating of polyethylene mixed with, for example, titanium dioxide, is applied over the initial colored coating in the form of a tetrachloroethylene solution, at a temperature below 80 C. After removal of the solvent, a white or lightly colored coating is applied to the reverse side of the sheet. This coating consists of microcrystalline wax to which titanium dioxide or other light colored pigment may be added as a brightener. If desired, other materials may also be included in the coating, as for example, magnesium stearate for the purpose of increasing the adherence of the coating.

The present invention relates to transfer sheets and to a method of transferring typewriting and handwriting by means of these sheets without the use of carbon paper or copying paper placed between the sheets, and to a method of making such transfer sheets. More particularly, it relates to sets of such sheets so arranged that a number of copies can be made at one typing or copying operation.

The present application is a continuation-in-part of my US. patent application Ser. No. 243,466, filed Dec. 16, 1962, now 3,226,134, and of my US. Ser. No. 498,978, filed Oct. 20, 1965, now abandoned.

Copying processes are already known in which copying papers, for example, carbon papers of various kinds, hectograph papers, and the like, are used. The reverse sides of such papers are provided with a specially hard ink layer or with a resin coating over the usual ink layer. Such copying papers are intended to be used in conjunction with paper the surface of which carries a wax coating which is intended to receive the copy. Such a process involves the use of ordinary carbon paper ink mixtures.

Transfer sheets are also known for multiple reproduction by the pressure of the writing, in which a transfer composition is applied to the reverse side of the writing sheet, a similar or contrasting color composition being applied to the upper surface of the next sheet below it. When writing is applied to the first sheet the writing is supposed to be transferred to the top surface of the sheet below it, without using special intermediate layers, such as, for example, carbon papers. Reproduction papers of this type used as the coating on the reverse side of the sheet clay, chalk, or a similar material, applied in powder form, while the surface of the second sheet was provided with a darker coating of contrasting color. Such sheets have been quite unsatisfactory since the layers so formed are quite unstable and, for example, are altered by mois ture when they come in contact with the latter.

Still another kind of reproduction paper has been described which transfers copies by the application of heat and pressure, after which any customary type of paper can be used for making additional copies. In this process, the ink coating is softened by raising the temperature and transferred in the form of a copy, the ink being used with resins, synthetic plastics, and like substances. The printing ink comprises pigments and organic dyes such as methyl violet and plasticizers and solvents may also be used. Such processes are highly impractical because of the necessity of heating the material used for transferring the writing.

A transfer paper is also known in which an ink layer is kept soft. The composition of such layers is similar to that of a carbon paper ink and is bonded by means of film-forming synthetic plastic substances. By exerting a writing pressure this ink layer transfers copies to ordinary paper. The ink layer of the original sheet comprises synthetic plastic substances, plasticizers, solvents, and the like. In this process, two elements are necessary, one being a conveyor or transfer means for the ink, and the other an essentially liquid ink composition, which is mechanically held fast to the conveyor means.

According to still another process, a sheet suitable for writing on and for transfer purposes is produced by applying on the upper side of a white or lightly colored sheet, that is, the side turned towards the writing instrument, a coating consisting, for example, of a polyvinyl acetate or highly acetylized, strongly colored derivative thereof, by brushing, spraying or other suitable method. This layer is then coated with a white or contrasting colored layer which is fast to handling or rubbing. This may consist of a polyvinyl chloride, e.g. polyvinylidene chloride, to which can be added, if desired, to intensify the white tone, a suitable substance such as titanium dioxide, aluminum spar, silicon spar, or the like. The opposite side of the sheet is provided with a thin layer of polyethylene having a molecular weight of 2000-5000 and a melting point of -ll0 C.

When using several superimposed sheets of the kind just described, in which the polyvinyl acetate or polyvinyl acetal side is turned towards the writing instrument, the writing pressure results in the removal of the comparatively brittle polyvinyl covering layer of the receiving sheet so that in the places where this covering layer is removed the strong coloration of the polyvinyl acetate or polyvinyl acetal layer lying underneath becomes visible.

Reproduction sheets of the above type have the disadvantage that the water-proofness and rubbing stability of the covering layer consisting of polyvinyl chloride or poly'vinylidene chloride, applied over the dye layer, is limited. This is especially the case when the said covering layer is applied in the form of aqueous solutions. The deposition of the covering layer in the form of an alcoholic solution, on the other hand, has the disadvantage that the ingredients of the dye layer which are alcohol soluble will be dissolved, and that the bond between the two layers becomes so strong that removal of the white coating layer by the action of the writing pressure is not satisfactory.

It has now been found, in accordance with the present invention, that reproduction sheets of the above type can be materially improved in the following manner.

Instead of forming the dye layer by applying the coloring matter with the aid of polyvinyl acetate or polyvinyl acetal, the dye layer containing pigments or dyes, e.g., carbon black, to which may be added titanium dioxide or other material so as to give any desired color hue, can be applied, according to the present invention, by using a solution of polyethylene, having a molecular weight of 2000-5000 and a melting point of 90ll0 C. in tetrachloroethylene containing the color ingredients such as dyes, the coating solution being applied at a temperature of 80 C., or higher. After deposition of the heated solution the solvent is removed by evaporation, preferably by passing the coated sheet over heated rolls, which simultaneously forms a strong bond between the dye layer and the paper.

On the dye layer, described above, is next applied as a coating layer a solution of polyethylene, having a molecular weight of 2000-5000 and a melting point of 90ll0 C., in tetrachloroethylene containing brightening agents such as, for example, titanium dioxide, barium sulfate, zinc oxide, lithopone, and the like, in order to increase the contrast against the underlying dye layer. It is important, however, that the temperature of the solution when applied be substantially below 80 C., i.e., below the temperature at which the dye layer was deposited from the polyethylene-tetrachloroethylene solution, and preferably at room temperature. The evaporation of the tetrachloroethylene solvent may then be accelerated by blowing a stream of cool air over the coating. This method of deposition and removal of the tetrachloroethylene from the coating layer does not dissolve the polyethylene used as the binder for the dye layer, or even to soften the surface thereof, tetrachloroethylene dissolving polyethylene noticeably only at about 80 C.

The deposition of the coating layer, as above described, at a relatively low temperature, gives a relativel loose binding of the coating layer to the underlying dye layer, with the result that the removal of the coating composition by the action of the writing pressure occurs with sharp outlines as well as completely. The letters or symbols thus formed are accordingly more sharply delineated, due to the open exposure of the dye layer.

It has further been found, in accordance with the present invention, that when the dye ingredients and the coating layer are deposited from a solution of polyethylene in tetrachloroethylene, the very clearest and most complete lifting off of the brittle polyethylene layer under the writing pressure will result when the reverse side of the writing sheet and of the copying sheets are covered with a layer of microcrystalline substances (i.e. having particle sizes ranging from 1 to 5 microns in diameter). Materials particularly suitable for this purpose include microcrystalline waxes, such as, for example, microcrystalline ozocerites, paratfins, ceresin, isoceresin, and the like. With these waxes, or mixtures thereof, may be included emulsifying or wetting agents, such as, for example, the metal stearates as magnesium stearate, which serve to increase the adherence (i.e., the lifting effect) of the microcrystalline waxes to the coating layer of the underlying copy sheet. Brightening agents, such as, for example, titanium dioxide, may also be included for the purpose of brightening the waxlayer.

In the above described procedure, the use of tetrachloroethylene as a solvent in the production of both the dye layer and the coating layer is particularly advantageous, as compared to the use of alcohol as a solvent, because of its noninfiammability, its relatively low toxicity, its rapid rate of evaporation, which permits increased rates of production of both dye and coating layers, and the fact that its use results in the formation of uniform and dense dye layers.

When using several superimposed sheets of the above described kind, it is, of course, unnecessary that both sides of the top and bottom sheets be coated, the upper layers being omitted from the top sheet and the microcrystalline wax layer being omitted from the bottom sheet.

In the manufacture of reproduction sheets of the type described above paper of any of the kinds customarily used for this purpose may be employed. Preferably, a 20-60 gram paper either sized or unsized and not translucent is used. Such a paper is first coated on its upper side with a solution of the above-designated type of polyethylene in tetrachloroethylene containing pigments or dyes, such as, for example, carbon black, Cadmium Red, Chromium Green, cinnabar, ultramarine, etc. After this color coating has dried, a white or contrasting color coating layer consisting preferably of polyethylene mixed with titanium dioxide is applied over the dye layer using tetrachloroethylene as the solvent, to give a coating layer corresponding to about 2-6 grams per square meter. The first, or dye layer coating is applied at a temperature above C. and the second or covering layer coating is applied at a temperature below 80 C., and preferably at room temperature.

Next, a white or lightly colored layer, consisting of microcrystalline wax or a mixture of such substances, is applied, preferably in the form of a melt, to the reverse sides of the above described sheets to a thickness corresponding to about 3 to 7 grams per square meter. If other materials are used in the coating at least 60% by weight of the coating should consist of microcrystalline waxes.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawing. It will be evident, however, that various modifications of the specific operations described will be obvious to one skilled in the art. Any such modifications which do not depart from the basic scope of the disclosed invention are intended to fall within the scope of the appended claims.

The essential modifications regarding the formation of reproduction transfer sheets in acordance with the present invention are as follows:

(I) Composition of the dye layer which is directly applied on a carrier sheet, e.g., on a sheet of paper;

(a) coloring materials-dark colored pigments or dyes which may be mixed with lighter colored materials to give different shades of color, e.g., carbon black used alone or mixed with varying amounts of titanium dioxide;

(b) bonding agent-polyethylene having a molecular weight of 2000-5000 and a melting point of -ll0 0., dissolved in tetrachloroethylene.

The coloring material, binding agent and solvent are applied to the sheet at a temperature of 80 C., or above. After application of the dye layer the solvent is removed therefrom by evaporation, preferably by passing the coated sheet over heated rolls.

(II) Composition of the White or lightly colored covering layer: This covering layer consists of polyethylene alone or in admixture with other binding agents, such as, for example, copolymer -vinyl compounds such as polyvinyl chlorides, mixtures of polyvinyl chlorides and polyvinyl acetals, mixtures of polyvinyl chlorides with polyvinyl alcohols, etc., wherein the amount of polyethylene is in excess of 50% by weight of the total binder. The covering layer is applied in the form of a tetrachloroethylene solution of polyethylene or mixture thereof with other binding agent and pigment such as titanium dioxide. The coating is applied over the dye layer while at a temperature substantially below 80% C., and preferably at room temperature.

(HI) Composition of layer on reverse side of sheet: Microcrystalline substances such as microcrystalline waxes as microcrystalline ozocerites, paraffins, ceresin, isoceresin, the amount of microcrystalline waxes in such coating layer being at least 60% by weight. Other bond ing agents and pigments to give brightening may also be included.The layer is preferably applied in melt form.

Specific examples of each of the above types of layers are given below under the headings shown above.

In the appended drawings:

FIG. 1 shows diagrammatically and in section a copying sheet embodying the invention.

FIG. 2 shows in diagrammatic representation a writing pad consisting of three superimposed writing sheets in accordance with FIG. 1.

FIG. 3 corresponds to an embodiment of the invention showing a dye layer covered with a coating layer on one side of the sheet and a layer of microcrystalline substances on the reverse side thereof.

FIG. 4 shows diagrammatically a typewriter roll with four superimposed copying sheets formed as in FIG. 1, which are rolled up in roll form,

In FIG. .1 the reference numeral 1 designates a sheet of white or lightly colored paper. The sheet is covered on the side turned toward the typewriter or pen with a colored layer 2, consisting, for example, essentially of carbon black suspended in polyethylene. On this layer is applied a white covering layer of polyethylene suspended in tetrachloroethylene, while the reverse side of the sheet 1 is provided with a layer 4 consisting of microcrystalline wax.

In FIG. 2 like reference numbers indicate the same components as in FIG. 1. Here three sheets of paper 1a, 1b, 10, formed as in FIG. 1, are superimposed in such a manner that the brittle covering layer 311, 3b, 3c of the color layers 2a, 2b, 2c in each case is lying against the adhesive layer 4a, 4b, 4c of the superimposed sheet.

In FIG. 3 the sheet of paper 10 is covered on the side turned towards the typewriter or pen with a colored layer 11 applied by means of a solution of polyethylene in tetrachloroethylene containing the dye ingredients. This dye layer is covered with the white coating layer 12 also deposited by means of a solution of polyethylene in tetrachloroethylene. In this case the reverse side of the sheet 10 is covered with the layer 13 consisting of a mixture of microcrystalline waxes and paraffin containing at least 60% by weight of the microcrystalline waxes.

In FIG. 4 four sheets 5, 6, 7, 8 of the kind shown in FIG. 1 or 3 are superimposed and rolled up in the form of a roll 9, from which they are gradually drawn off in the course of writing. The proposed construction of copying sheets offers, by contrasts with the usual copying 'processes, the advantage of dispensing with separate carbon or copying sheets. This is particularly advantageous in writing sets of individual or endless forms, for example, fan-shaped sets or typewriter rolls, as here both the insertion of the carbon sheets and their removal after the writing is completed, is completely dispensed with.

In producing the copy sheets of the present invention the coating can be applied by conventional methods, as for example, by brushing, spraying, rolls, doctor blades, or other suitable method.

The layers may be full surface, or in strips as desired, or they may be aplied so as to leave gaps. Furthera more, undesired copyings and imprints can be prevented at given places, by covering, for example, at will, the front or reverse side with suitable means, for example, by printing over.

An interchange of the sides of the foil can be prevented by providing one or both sides with a suitable identifying mark at the margin. In assembling the sets of forms it is then only necessary to take care that the layer 4 of the upper sheet always lies on the layer 3 of the writing sheet placed underneath as in FIG. 2. This method also permits the production of transfer sheets in many colored variations. In particular, it may be mentioned, for example, that by leaving out the layer 2 and strongly coloring layers 3 and 4 a white image of the writing can be obtained.

Specific compositions for the various layers are shown below.

(I) DYE LAYER Parts by weight Polyethylene 1.0-2 .5 Tetrachloroethylene 92.085.0 Carbon black 2.0-5.5

Titanium dioxide 5.0-7.0

Parts by weight Polyethylene 1.5 Tetrachloroethylene 90.0 Carbon black 3.5

Titanium dioxide 5.0

Parts by weight Polyethylene 1.5 Tetrachloroethylene 90.0 Ultramarine 8.5

Parts by weight Polyethylene 2.0 Tetrachloroethylene 87.0 Carbon black 6.0

Titanium dioxide 5.0

(II) DYE COATING LAYER Parts by weight Polyethylene 1.7-3 .0 Tetrachloroethylene 60.8492 Titanium dioxide 30.0-40.0

Vinofiex 1 7.5-7.8

1 Product of the BASF type MP 400 comprising a polymer of vinyl chloride and vinyl isobutyl ether.

Parts by weight Polyethylene 2.5 Tetrachloroethylene 62.5 Titanium dioxide 35.0

(III) COATING FOR REVERSE SIDE Parts by weight Microcrystalline wax (synthetic wax) 60 Rosin ester resin l0 Polyvinyl ethyl ether 30 Parts by weight Ceresine wax 90.0

Parafiin wax 10.0

What is claimed is:

I. A manifold sheet comprising: (a) a paper sheet base, (b) a color layer comprising a color-forming material selected from pigments and dyes deposited on one side of said sheet base and bonded thereto by polyethylene having a molecular weight of 20005000 and a melting point of 90110 C., (c) a relatively loosely bound covering layer deposited on said color layer and comprising a pigment contrasting in color with said color layer and bonded thereto with polyethylene having a molecular weight of 20005000 and a melting point of 90110 C., and (d) on the reverse side of said paper sheet base a coating comprised of microcrystalline waxes.

2. A manifold sheet according to claim 1, wherein the color layer comprises materials selected from the group consisting of carbon black, titanium dioxide, Cadmium Red, Chromium Green and cinnabar.

3. A manifold sheet according to claim 1, wherein the color covering layer comprises materials selected from the group consisting of titanium dioxide, zinc oxide, barium sulfate and lithopone.

4. A manifold sheet according to claim 1, wherein the coating on the reverse side of the sheet comprises materials selected from the group consisting of microcrystalline ozocerites, ceresine, isoceresine and parafiins.

5. The process of preparing manifold copy sheets which comprises applying at a temperature not substantially below 80 C. to one side of a paper base sheet a colorforming layer composition comprising a polyethylene having a molecular weight of 2000-5000 and a melting point of 90110 C., tetrachloroethylene, and a color-forming material selected from pigments and dyes, removing said tetrachloroethylene solvent from said deposited coating by evaporation, applying at a temperature substantially below 80 C. to said dried color layer a coating composition comprising a pigment having a color contrasting with the color of said color layer, tetrachloroethylene and a polyethylene having a molecular weight of 2000-5000 and a melting point of 90110 C., drying the said applied coating composition and applying to the reverse side of said coated sheet a coating of microcrystalline materials.

6. A process of preparing manifold sheets according to claim 5, wherein the color-forming layer composition comprises tetrachloroethylene, a polyethylene having a molecular weight of 2000-5000 and a melting point of 90-1 10 C. and color-forming materials selected from the group consisting of carbon black, titanium dioxide, Cadmium Red, Chromium Green and cinnabar.

7. A process of preparing manifold copy sheets according to claim 5, wherein the coating composition for covering said dried color layer comprises tetrachloroethylene, a polyethylene having a molecular weight of 2000-5000 and a melting point of 90110 C. and materials selected 8 from the group consisting of titanium dioxide, zinc oxide, barium sulfate and lithopone.

8. A process of preparing manifold copy sheets according to claim 5, wherein the microcrystalline materials are selected from the group consisting of microcrystalline ozocerites, ceresins, isoceresins, and paraffins.

9. A process of preparing manifold copy sheets according to claim 5, wherein the microcrystalline substances are applied to the reverse side of said sheet in melt form.

References Cited UNITED STATES PATENTS 3,203,832 8/1965 Mino et a1. 11736.3 3,226,134 12/1965 Breidthardt 1 1736.4 3,243,312 3/1966 Schutzner et al. 11736.3 3,256,108 6/1966 Strauss 117-363 3,294,571 12/1966 Ernest 11736.3 3,340,086 5/1967 Groak 117-36.4 3,418,148 12/1968 Barz 117--36.4

MURRAY KATZ, Primary Examiner US. Cl. X.R. 11736.4, 76, 155 

